What to measure
How to use the grass seed calculator
Measure the lawn as a rectangle or circle, then pick the grass type and choose new lawn or overseeding. Set the bag size you plan to buy to see how many bags.
The formula
Pounds of seed = area (sq ft) ÷ 1,000 × seeding rate. Halve it for overseeding.
Worked example: 50 × 40 ft new tall fescue lawn
- 50 × 40 = 2,000 sq ft
- 2,000 ÷ 1,000 × 6 lb = 12 lb of seed → 3 bags of 5 lb
- Overseeding the same lawn: 6 lb
Seeding rates we use (new lawn)
| Grass | lb per 1,000 sq ft |
|---|---|
| Tall fescue | 6 |
| Kentucky bluegrass | 2 |
| Bluegrass + perennial ryegrass | 2.5 |
| Bermudagrass (hulled) | 1.5 |
Rates come from NC State Extension. Seed blends vary, so when your bag lists a rate, use it.
Grass seed by lawn size
Pounds for a new lawn. Halve them for overseeding.
| Lawn area | Tall fescue | Kentucky bluegrass | Bermudagrass |
|---|---|---|---|
| 1,000 sq ft | 6 lb | 2 lb | 1.5 lb |
| 2,500 sq ft | 15 lb | 5 lb | 3.8 lb |
| 5,000 sq ft | 30 lb | 10 lb | 7.5 lb |
| 10,000 sq ft | 60 lb | 20 lb | 15 lb |
| 1 acre (43,560 sq ft) | 261.4 lb | 87.1 lb | 65.3 lb |
Common mistakes
- Using a new-lawn rate to overseed. An existing lawn needs about half as much; the extra seed only crowds the seedlings.
- Ignoring the rate on the bag. Blends and coated seed differ from the plain rates above. When the bag gives a rate, use it.
- Spreading in one pass. Split the seed in half and spread it in two directions for even cover.
- Measuring the whole lot. Subtract the house, driveway and beds; only the area you’ll seed counts.
Frequently asked questions
How much grass seed per 1,000 square feet?
About 6 lb of tall fescue, 1–2 lb of Kentucky bluegrass, 2.5 lb of a bluegrass–ryegrass mix and 1–2 lb of hulled bermudagrass for a new lawn (NC State Extension). Coated seed may need up to double.
How much seed do I need to overseed?
About half the new-lawn rate. For 2,000 sq ft of tall fescue that's 6 lb instead of 12.
Is more seed better?
No. Seeding heavier than recommended produces crowded, weak seedlings that are more prone to disease. Follow the rate on the bag.
When should I plant grass seed?
Cool-season grasses (fescue, bluegrass, ryegrass) in early fall, with spring as second best. Warm-season grasses like bermudagrass in late spring to early summer.
How much grass seed do I need for an acre?
An acre is 43,560 sq ft. For a new tall fescue lawn that's 261.4 lb (6 bags of 50 lb), or 130.7 lb for overseeding. Kentucky bluegrass needs 87.1 lb for a new lawn.
How much grass seed for 5,000 square feet?
For a new lawn, 30 lb of tall fescue, 10 lb of Kentucky bluegrass, 12.5 lb of a bluegrass and ryegrass mix or 7.5 lb of hulled bermudagrass.
How much seed to overseed 1,000 square feet?
Half the new-lawn rate, which is 3 lb of tall fescue, 1 lb of Kentucky bluegrass, about 1.3 lb of a bluegrass and ryegrass mix or 0.8 lb of hulled bermudagrass.
How many bags of grass seed for 10,000 square feet?
For a new tall fescue lawn, 60 lb, which is 12 bags of 5 lb. Overseeding takes 30 lb, or 6 bags. Kentucky bluegrass needs 20 lb for a new lawn.
Sources
Formulas and defaults last reviewed October 30, 2026. How we check our math.